A fuel cell stack, part of a fuel cell power plant known to the prior art, is illustrated in FIG. 1. The fuel cell stack 7 includes a pressure or end plate 8, a fuel inlet/outlet manifold 9, a fuel turn manifold 10, and air/coolant inlet/outlet manifold 11 and an air turn manifold 12. The manifolds 9-12 are sealed to the edges of the fuel cells 14 and the edges of the pressure plate 8 by means of foam gaskets, silicone rubber, and possibly other components, examples of which are shown in U.S. Pat. No. 7,112,384. The pressure plates are drawn together by tie rods 15, as is known the manifolds are pressed to the stack by load cables or straps 17. The air/coolant manifolds experience leakage near the center line of the stack 18 because the manifolds have a low profile (that is, a low top-to-bottom height as seen in FIG. 1) and are therefore not stiff enough to counter the seal preload and stack pressure loads, thereby deflecting enough to leak in the center.
In motor vehicle applications, the volume of the fuel cell power plant is severely limited so that the size of the manifolds as well as any corrective equipment, such as clamps is highly restricted.